The nature of eukaryotic differentiation and development will be explored by studying the cAMP binding proteins - their appearance, properties and functions - during the development of Dictyostelium discoideum, a cellular slime mold. The cAMP binding proteins will be studied by photoaffinity labeling using azido-cAMP as a photoaffinity agent. A protease which breaks down the cAMP binding proteins will also be studied using labeled cAMP binding proteins as substrates. The development of protein kinase activity, and its relation to the cAMP binding proteins will also be studied. Although this is a biological-biochemical problem of a very basic nature, it has many health related implications as the appearance of cAMP as a regulatory agent appears to be quite extensive and any understanding of its role in development and differentiation may have important implications for understanding of these processes in human beings.